syzbot

======================================================
WARNING: possible circular locking dependency detected
6.11.0-rc3-syzkaller-00279-ge5fa841af679 #0 Not tainted
------------------------------------------------------
kswapd0/90 is trying to acquire lock:
ffff88808549ed98 (&xfs_nondir_ilock_class#3){++++}-{3:3}, at: xfs_can_free_eofblocks+0x5f1/0x8d0 fs/xfs/xfs_bmap_util.c:550

but task is already holding lock:
ffffffff8e82e3a0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6841 [inline]
ffffffff8e82e3a0 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xb06/0x2e80 mm/vmscan.c:7223

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (fs_reclaim){+.+.}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
       __fs_reclaim_acquire mm/page_alloc.c:3823 [inline]
       fs_reclaim_acquire+0x88/0x140 mm/page_alloc.c:3837
       might_alloc include/linux/sched/mm.h:334 [inline]
       slab_pre_alloc_hook mm/slub.c:3939 [inline]
       slab_alloc_node mm/slub.c:4017 [inline]
       __do_kmalloc_node mm/slub.c:4157 [inline]
       __kmalloc_noprof+0xa9/0x400 mm/slub.c:4170
       kmalloc_noprof include/linux/slab.h:685 [inline]
       xfs_attr_shortform_list+0x753/0x1900 fs/xfs/xfs_attr_list.c:117
       xfs_attr_list+0x1d0/0x270 fs/xfs/xfs_attr_list.c:595
       xfs_vn_listxattr+0x1d2/0x2c0 fs/xfs/xfs_xattr.c:341
       ovl_copy_xattr+0x1a2/0xb60 fs/overlayfs/copy_up.c:98
       ovl_copy_up_metadata+0x24f/0xda0 fs/overlayfs/copy_up.c:650
       ovl_copy_up_tmpfile fs/overlayfs/copy_up.c:870 [inline]
       ovl_do_copy_up fs/overlayfs/copy_up.c:976 [inline]
       ovl_copy_up_one fs/overlayfs/copy_up.c:1168 [inline]
       ovl_copy_up_flags+0x1eba/0x4470 fs/overlayfs/copy_up.c:1223
       ovl_open+0x142/0x2a0 fs/overlayfs/file.c:154
       do_dentry_open+0x970/0x1440 fs/open.c:959
       vfs_open+0x3e/0x330 fs/open.c:1089
       do_open fs/namei.c:3727 [inline]
       path_openat+0x2b3e/0x3470 fs/namei.c:3886
       do_filp_open+0x235/0x490 fs/namei.c:3913
       do_sys_openat2+0x13e/0x1d0 fs/open.c:1416
       do_sys_open fs/open.c:1431 [inline]
       __do_sys_openat fs/open.c:1447 [inline]
       __se_sys_openat fs/open.c:1442 [inline]
       __x64_sys_openat+0x247/0x2a0 fs/open.c:1442
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&xfs_nondir_ilock_class#3){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3133 [inline]
       check_prevs_add kernel/locking/lockdep.c:3252 [inline]
       validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3868
       __lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
       down_read_nested+0xb5/0xa50 kernel/locking/rwsem.c:1651
       xfs_can_free_eofblocks+0x5f1/0x8d0 fs/xfs/xfs_bmap_util.c:550
       xfs_inode_mark_reclaimable+0x1bb/0xf60 fs/xfs/xfs_icache.c:2148
       destroy_inode fs/inode.c:313 [inline]
       evict+0x809/0x950 fs/inode.c:729
       dispose_list fs/inode.c:747 [inline]
       prune_icache_sb+0x239/0x2f0 fs/inode.c:932
       super_cache_scan+0x38c/0x4b0 fs/super.c:223
       do_shrink_slab+0x701/0x1160 mm/shrinker.c:435
       shrink_slab_memcg mm/shrinker.c:548 [inline]
       shrink_slab+0x878/0x14d0 mm/shrinker.c:626
       shrink_node_memcgs mm/vmscan.c:5910 [inline]
       shrink_node+0x130f/0x2df0 mm/vmscan.c:5948
       kswapd_shrink_node mm/vmscan.c:6762 [inline]
       balance_pgdat mm/vmscan.c:6954 [inline]
       kswapd+0x191b/0x2e80 mm/vmscan.c:7223
       kthread+0x2f0/0x390 kernel/kthread.c:389
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(fs_reclaim);
                               lock(&xfs_nondir_ilock_class#3);
                               lock(fs_reclaim);
  rlock(&xfs_nondir_ilock_class#3);

 *** DEADLOCK ***

2 locks held by kswapd0/90:
 #0: ffffffff8e82e3a0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6841 [inline]
 #0: ffffffff8e82e3a0 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xb06/0x2e80 mm/vmscan.c:7223
 #1: ffff8880656d60e0 (&type->s_umount_key#56){++++}-{3:3}, at: super_trylock_shared fs/super.c:562 [inline]
 #1: ffff8880656d60e0 (&type->s_umount_key#56){++++}-{3:3}, at: super_cache_scan+0x94/0x4b0 fs/super.c:196

stack backtrace:
CPU: 1 UID: 0 PID: 90 Comm: kswapd0 Not tainted 6.11.0-rc3-syzkaller-00279-ge5fa841af679 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2186
 check_prev_add kernel/locking/lockdep.c:3133 [inline]
 check_prevs_add kernel/locking/lockdep.c:3252 [inline]
 validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3868
 __lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
 down_read_nested+0xb5/0xa50 kernel/locking/rwsem.c:1651
 xfs_can_free_eofblocks+0x5f1/0x8d0 fs/xfs/xfs_bmap_util.c:550
 xfs_inode_mark_reclaimable+0x1bb/0xf60 fs/xfs/xfs_icache.c:2148
 destroy_inode fs/inode.c:313 [inline]
 evict+0x809/0x950 fs/inode.c:729
 dispose_list fs/inode.c:747 [inline]
 prune_icache_sb+0x239/0x2f0 fs/inode.c:932
 super_cache_scan+0x38c/0x4b0 fs/super.c:223
 do_shrink_slab+0x701/0x1160 mm/shrinker.c:435
 shrink_slab_memcg mm/shrinker.c:548 [inline]
 shrink_slab+0x878/0x14d0 mm/shrinker.c:626
 shrink_node_memcgs mm/vmscan.c:5910 [inline]
 shrink_node+0x130f/0x2df0 mm/vmscan.c:5948
 kswapd_shrink_node mm/vmscan.c:6762 [inline]
 balance_pgdat mm/vmscan.c:6954 [inline]
 kswapd+0x191b/0x2e80 mm/vmscan.c:7223
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>